said by asdfdfdfdfdf :
I understand what you are saying but surely the question of who is allocated this spectrum matters. The problem, it seems to me, is not that lightsquared has moved into spectrum allocated to gps but that gps is relying upon spectrum assets that were not allocated to it.
That is not correct.
Lightsquared has moved into spectrum that is not allocated to Lightsquared, i.e., the spectrum is allocated to satellite to ground use, not ground to ground use, and the spectrum on the ground is for satellite to ground use.
Look at Microwave point to point spectrum. It has a physical vector, i.e., a direction of transmission. You aren't allowed to use spectrum Milky-Way wide; a spectrum allocation has necessary LOCATION and STRENGTH components. You CANNOT ignore this, as physics dictates these realities, and the FCC has allocated per this reality. There are almost no world-wide spectrum allocations, and extremely few USA-wide allocations, but my point is more that a spectrum allocation has necessary LOCATION, DIRECTION, and STRENGTH components. Thus to look only at FREQUENCY is bogus.
Furthermore, as others have pointed out, the satellite use of the GPS spectrum INCLUDES Doppler-shifted transmissions, which are OK as a satellite-to-ground transmission to be found in the expected location due to the shift, i.e., somewhat different than the transmission bands allocated. This was known at the time of allocation, and it was also known that this is OK because of the type of lack of interference that neighboring satellite to ground spectrum would cause, and because that is how that spectrum and transmission method works.
The bad thing happened when Lightsquared tried to use spectrum that was not allocated to them, i.e., ground to ground spectrum that interferes with the GPS signals. You cannot argue with Physics, and the FCC used to understand that very well. Anybody currently in the FCC who ignores physics with the GPS system is liable to be munched with this fiasco, and anybody trying to pretend that location, direction, and strength do not matter can have their wives and children ground up in meat grinders for all I care.